Document Detail

The role of humoral and cellular immune factors in neuromuscular block in myasthenia gravis.
MedLine Citation:
PMID:  786115     Owner:  NLM     Status:  MEDLINE    
The neuromuscular block of myasthenia gravis appears to be due to decreased and abnormal responsiveness of the motor end plates to transmitter, and perhaps a decreased number of functioning end plates. The presence in myasthenic patients of serum globulins that bind to a bariety of cellular and subcellular components, and of thymic abnormalities, has encourage the search for humoral and cellular immune factors that may be responsible for the anatomic and functional defects. Attempts to demonstrate neuromuscular blocking activity in the serum have been inconclusive. While 30% to 48% of myasthenic patients have globulins that react with muscle membrane, striations, ribonucleporotein, and thymic epithelial cells, these globulins have not been shown to react with the end plate or acetylcholine receptor, or to impair neuromuscular transmission. Antinuclear, rheumatoid, antimitochondrial antithyroid, anti-smooth-muscle, and anti-gastric-parietal cell factors are found in the serum of 3% to 16% of myasthenic patients, but these are much more commonly present in other diseases. However, antibodies to acetylcholine receptor from electric tissue, which were recently reported in the serum of three fourths of myasthenic patients, may prove to be more directly related to the neuromuscular block. While the majority of myasthenic patients have thymic abnormalities, including thymoma in 9% of patients and hyperplastic thymus in 66% of patients, the remaining 25% of patients have normal, involuted, or undetectable thymus. Thymectomy has a favorable effect in about two thirds of myasthenic patients, but about one third of patients have no benefit. Thirty-two patients have been described who developed myasthenia gravis after total thymectomy and presumably in the absence of the thymus. Thymus lymphocytes of myasthenic patients have some differences from those of normal subjects, including a greater proportion of B cells, but their significance is not known. Attempts to demonstrate neuromuscular blocking activity in the thymus of myasthenic patients have been inconclusive. Blood lymphocytes of myasthenic patients also have some differences from those of normal subjects, including a lower proportion of T cells. The proportion of both T and B cells increased following thymectomy. While studies on the immunological reactivity of lymphocytes from myasthenic patients have shown some differences from those of normal subjects, neuromuscular blocking activity has not been demonstrated in these cells or in their extracts. There is increasing evidence that the neuromuscular block of myasthenia gravis is due to alteration of the acetylcholine receptor. The recent reports of antibodies to acetylcholine receptor in the serum of myasthenic patients suggests that these may be responsible for the neuromuscular block, but such action, and the cause of antibody release, remain to be determined.
T Namba; Y Nakata; D Grob
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Annals of the New York Academy of Sciences     Volume:  274     ISSN:  0077-8923     ISO Abbreviation:  Ann. N. Y. Acad. Sci.     Publication Date:  1976  
Date Detail:
Created Date:  1976-10-20     Completed Date:  1976-10-20     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  7506858     Medline TA:  Ann N Y Acad Sci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  493-515     Citation Subset:  IM    
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MeSH Terms
B-Lymphocytes / physiology
Immunity, Cellular*
Lymphocyte Activation
Membranes / immunology
Muscles / immunology
Myasthenia Gravis / blood,  complications,  immunology*,  physiopathology
Neuromuscular Junction / immunology*,  physiopathology
Serum Globulins / immunology
T-Lymphocytes / physiology
Thymoma / complications,  immunology
Thymus Extracts / pharmacology
Thymus Gland / physiopathology
Thymus Hyperplasia / immunology
Thymus Neoplasms / complications,  immunology
Reg. No./Substance:
0/Serum Globulins; 0/Thymus Extracts

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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